1. Field of the Invention
The invention relates to a conveyor installation having    a) at least one transporting unit that is displaceable along a conveying path and that comprises an entrained electrical load, and having    b) a busbar that is arranged along the conveying path and that comprises at least one power supply contact conductor by means of which the transporting unit is supplied with power.
2. Description of the Prior Art
An example of a conveyor installation of this kind is an electric telpher line, in the case of which a support running along the conveying path has usually a multiplicity of transporting units suspended from it that each have a drive of their own in order to compel themselves independently. The transporting units are in this case supplied with the power required for the propulsion by means of a busbar running along the conveying path, which busbar has sliding contacts of the transporting units engaging with it. An electric telpher line of this kind is therefore often also referred to as a busbar-powered conveyor installation.
Most conveyor facilities of this kind are operated in mixed work environments in which both partially or fully automated transporting units and human beings are moving. In order to protect the human beings from injuries, particularly as a result of movements by the transporting units, the conveyor facilities comprise safety devices that provide different safety functions.
There are increased demands on the reliability of such a safety device. These demands are defined by means of the DIN EN ISO 13849 standard, for example. In particular, this standard requires the overall design of a safety function, such as the possibility of triggering an emergency stop for the transporting units, for example, to ensure that not one single fault in one of the parts relevant to the safety function results in said safety function not being performed correctly. Further, the safety function should be designed such that a fault that has occurred is detected at least before a fresh demand on the safety function.
For this purpose, the busbars of conveyor facilities known hitherto have two safety contact conductors by means of which a safety function, such as an emergency stop, for example, is realized in redundant fashion.
Since the installation space available for the busbar is limited in the conveyor facilities, however, it would be advantageous to reduce the number of contact conductors. In particular, installation space freed up thereby could be used for installing a position code, for example. In this regard, cf. DE 10 2010 056 521 A1 from the applicant. In addition, the cost involvement for such a busbar would be decreased.